IVIEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



459 



liiiuillon. — Clonded; adelicatc, almost invisible jiellicle forms on the suriaee, and there is a 

 tlocciilent, whitish sediment at the bottom. The boiiilhin ai(|uires a faint green cohjr. 



I'ufafi). — Rather dry, giamilar, elevated, widely spreadm;^- growth of about the same color as 

 the potato; the granular api)earanc(; seems to be due to minute wrinkles or folds; later the growth 

 may become brownish in color and viscid-looking. 



Litmns mill;. — Coagulated and dec'olorized; the clot is firm and the serum is clouded; there is 

 a pink ring on the wall of the tube and the clot may show some pink coloration after a time. 



Siujar (jelaiin in deep stab. — Very slight development. 



Rosolic acid. — Decolorized; reaction is neutral or alkaline. 



Indol production. — Fair reaction;, does not produce nitrites. 



Eelofioii to temperature. — Does not grow at 3-jO to 30^ C. 



Bacillus geniculatus. 



Isolated from the water of the Schuylkill Eiver. liare. A medium-sized motile bacillus, 

 occurring singly, in pairs, and sometimes in threads. It is a ]>olar flagellated bacillus, the number 

 of tlagella varying from one to probably four; no spore formation observed. 



Colonies iu (jelatiii. — About the second day the surface colonies are rounded, semitranslucent, 

 whitish disks, somewhat denser at the center and 1 mm. to 2 mm. in diameter. (PI. II, fig. it.) 

 They may already be slightlj' depressed in the gelatin; under a low power they are brownish and 

 granular about their centers, thinner at their margins, which are smooth or slightly wavy, and 

 sharply defined in colonies not j-et beginning to liquefy the gelatin, while in those which are, the 

 nuirgins are rugged and surrouiuled by a finely granular zone, apparently made up of delicate, 

 radiating- fibrils; the colonies soou get denser as liquefaction begins, and may have a greenish 

 shimmer. The deep colonies appear to the naked eye as yellow i)aints; under a low magnifying 

 power they are spherical, sharply defined, faintly granular, and are studded here and there by 

 smidl ])laques or buds. About the third day the colonies are circular in outline, grayish white 

 with yellowish centers, and several millimeters in diameter; they lie in saucer-sha])ed depressions 

 containing liquefied gelatin, a narrow zone of which surrounds them; later a pinkish tint may be 

 f)bserved at their centers; under a low power they are now granular, dark, and 

 dense, with a greenish shimmer, breaking up at the margin into a granular zone, 

 which is bounded by a more or less distinct fringe of radiating fibrils. Motion of a 

 circulatory character has been observed in the lirpiefie<I gelatin; the deep colonies, 

 when examined with the low power about this time, are rough looking, apjiarently 

 being made up of aggregations of small irregular clumi)s. an appearance which seems 

 to be the result of the budding process noted al)ove. ]\Iany have a dark center and 

 may show a reddish brown tint or a greenish sliimmer. 



Gelatin stab. — Liquefaction in funnel form extending slowly down the line of 

 inoculation; there may be a constriction at the top inclosing an air space (fig. 23). 

 The liquefied gelatin is clouded and there is an abundant whitish to pinkish deposit; 

 there may be a thin pellicle on the surfiice; the growth along the line of inoculation 

 preceding liquefaction has a pinkish tint, and may be eom])osed of discrete and con- 

 fluent spherical colonies. 



Aeid gelatiu. — Grows less vigorously and with slow licjuc^facticm, which does not 

 extend along the line of inoculation. 



Agar slant. — Grayish, shining, smooth surface growth, not spreading widely, 

 with wavy, bulging margins; it is semitranslucent by tiansnutted light. The agar acquires a 

 brownish green tint. 



Bouillon. — Clouded with lloccnli in .suspension, whicii at the surface may form an imperfect 

 liellide; the bouillon acijuires a slight greenish tint; there is a whitish sediment at the bottom. 



Potato. — Thin, viscid looking; moist, shining, brownish growth, not widely sjircading. 



Litmus w (7 A-.— Coagulated ami decolorized; there is a ])inkish yellow scum on some cloudy 

 serum; the clot is Jelly like: the serum after a time may have a slightly greenisli tint; there is a 

 l)luish ring on the tube wall; the reaction is alkaline. 



Fio.23. 



